An embodiment relates to a nonvolatile memory device and a method of operating the same.
In recent years, there has been an increasing demand for nonvolatile memory devices which can be electrically programmed and erased and do not require the refresh function of rewriting data at specific intervals.
The nonvolatile memory device is configured to enable electrical program and erase operations and perform the program and erase operations by varying threshold voltages when electrons are migrated by a strong electric field applied to a thin oxide layer.
The nonvolatile memory device mainly includes a memory cell array in which cells for storing data are arranged in a matrix form and a page buffer for writing data into specific cells of the memory cell array or reading data stored in specific cells. The page buffer includes a bit line pair coupled to specific memory cells, a register for temporarily storing data to be written into the memory cell array or reading data stored in specific memory cells from the memory cell array and temporarily storing the read data, a sense node for sensing the voltage level of a specific bit line or a specific register, and a bit line selection unit for controlling whether or not to couple the specific bit line to the sensing node.
With respect to a plurality of above-described page buffers included in a non-volatile memory device, whether a program has been completed is determined based on data stored in each of the page buffers. To this end, a pass/fail check operation is performed. If there is a failed cell on which the program has not been completed, a failed-state signal is output. How many failed cells exist in a target program page is checked by performing a column scanning operation in response to the failed-state signal. However, in conventional designs, the number of page buffers on which a column scanning operation must be performed when a failed-state signal is generated is large. Accordingly, a problem arises because the time that it takes to perform the column scanning operation is relatively long.